Former world number one Pliskova fell at first hurdle in the tune-up tournaments in Berlin and Eastbourne last month but the 29-year-old has yet to drop a set at Wimbledon.
Thursday's result was almost identical to Pliskova's win over Ostapenko in the 2018 quarter-finals in Stuttgart when the Czech went on to capture the title.
The 21-year-old qualifier, ranked 292nd, had won her first-ever tour-level match in the opening round of the WTA 500 event to set up the clash with Czech Pliskova in her first meeting with a top 100 player.
"It was not me on the court," Gasanova told reporters amid continuous giggles. "I was so sure of myself. I'm really happy right now.